Operating System (OS)

 

Operating System (OS)-

 

Definition

An Operating System (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. The OS is an intermediary between users and the computer hardware.

2. Functions of an Operating System:

• Process Management:
• Process Creation/Deletion: The OS handles the creation and termination of processes.
• Scheduling: The OS schedules processes in such a way that CPU utilization is maximized.
• Synchronization: It ensures that processes do not interfere with each other while running concurrently.
• Inter-process Communication (IPC): Enables processes to communicate and synchronize their operations.
• Memory Management:
• Memory Allocation/Deallocation: The OS manages memory allocation for processes, ensuring efficient utilization of RAM.
• Virtual Memory: Allows the OS to give the illusion of more memory than physically available, by using disk space as an extension.
• Paging and Segmentation: Techniques to manage and divide memory for better protection and organization.
• File System Management:
• File Organization: OS organizes files in directories for easy navigation and retrieval.
• File Access Control: It handles access permissions for files to prevent unauthorized access.
• File Storage: Manages file reading and writing, storage allocation, and disk management.
• Device Management:
• Device Drivers: OS manages hardware devices through device drivers.
• I/O Device Control: It ensures smooth communication between I/O devices (keyboard, printer, etc.) and the system.
• Spooling: Allows the OS to queue multiple jobs, like print jobs, and process them efficiently.
• Security and Protection:
• User Authentication: OS ensures that only authorized users can access the system.
• Access Control: Regulates which users can access certain resources and files.
• Data Protection: Protects data from unauthorized access through encryption and secure storage.
• User Interface:
• Graphical User Interface (GUI): Provides a visual interface that makes interaction with the system user-friendly.
• Command-Line Interface (CLI): A text-based interface that allows users to type commands to interact with the OS.

3. Types of Operating Systems:

1.    Batch Operating System

Some computer processes are very lengthy and time-consuming. To speed the same process, a job with a similar type of needs are batched together and run as a group.

The user of a batch operating system never directly interacts with the computer. In this type of OS, every user prepares his or her job on an offline device like a punch card and submit it to the computer operator.

2.    Multi-Tasking/Time-sharing Operating systems

Time-sharing operating system enables people located at a different terminal(shell) to use a single computer system at the same time. The processor time (CPU) which is shared among multiple users is termed as time sharing.

3.    Real time OS

A real time operating system time interval to process and respond to inputs is very small. Examples: Military Software Systems, Space Software Systems are the Real time OS example.

4.    Distributed Operating System

Distributed systems use many processors located in different machines to provide very fast computation to its users.

5.    Network Operating System

Network Operating System runs on a server. It provides the capability to serve to manage data, user, groups, security, application, and other networking functions.

6.    Mobile OS

Mobile operating systems are those OS which is especially that are designed to power smartphones, tablets, and wearables devices.

Some most famous mobile operating systems are Android and iOS, but others include BlackBerry, Web, and watchOS.